In an existing mobile phone, when a Global System for Mobile Communications (GSM) and a Global Positioning System (GPS) exist simultaneously, when a PA of the GSM transmits a signal, generated spurious emission affects a GPS receiving signal, where a carrier-to-noise-density ratio (CN0) value is used to indicate signal strength of the GPS receiving signal, and an amount of deterioration of the CN0 value is used to measure quality of a GPS receiver receiving signal, that is, a larger amount of deterioration of the CN0 value indicates worse quality of the GPS receiver receiving signal.
Therefore, each GPS chip manufacturer sets a PA blanking function on a GPS chip. When a mobile phone manufacturer enables the PA blanking function, the amount of deterioration of the CN0 value of the GPS is controlled within a range. However, when the GSM is working, a power control level (PCL) of the mobile phone and a quantity of slots (timeslots) both change. Therefore, when the PCL and a value of the quantity of slots are constant, the amount of deterioration of the CN0 value of the GPS when the PA blanking function is enabled may be greater than an amount of deterioration of the CN0 value of the GPS when the PA blanking function is disabled. Therefore, because the PA blanking function cannot be configured flexibly to an enabled state or a disabled state, the amount of deterioration of the CN0 value of the GPS increases, resulting in degradation of the quality of the GPS receiving signal.